The present invention relates generally to the transmission of audio/video television signals, and, in particular, to a wireless audio and video transmitter and receiver system apparatus capable of accepting both external baseband audio and video signal inputs and an external modulated audio/video signal modulated at a frequency corresponding to a particular television channel. In the present wireless audio and video transmitter and receiver system apparatus the transmitter transmits an AM modulated audio/video signal via an RF carrier in the 900 MHz band to one or more remote receivers which regenerate the original audio/video signal providing both baseband audio and video signal outputs as well as a modulated audio/video signal output at the particular television channel.
Advances in technology and manufacturing have resulted in the video cassette recorder (VCR) becoming virtually common place in households which own a television set. In homes owning multiple television sets, the VCR is typically placed adjacent to and hardwire connected to a single designated television set. Should one desire to view a video cassette, one has to view the video cassette on the particular television set to which the VCR is physically attached. Should one wish to view the video cassette on another television set, one alternative is to disconnect the VCR from its designated television set and reconnect the VCR to a remote television. Another alternative consists of hardwire connecting multiple television sets to a single VCR using multiple selector switches to "make" the desired connections to cause the VCR's audio/video signal to be directed to the desired television set. Likewise, if one desires to view a television program which is supplied to the homeowner via a cable television network, the television which the homeowner wishes to view must be connected to the cable television network.
In theft prevention and other security applications, where video cameras are utilized, video cameras must each be physically hardwired to a monitoring station, or recording device, often located at distances remote from the camera's location. In such situations, great lengths of connecting wire may be required, connections which are susceptable to damages over time and/or cutting by one attempting to defeat a security camera.
The limitations of such physical connections are apparent in that one must either physically move the VCR about the house or endure the expense and/or unsightliness of having wires run from television to television as well as risk damage to any connecting cables. Accordingly the present invention seeks to address these limitations by providing for the wireless transmission and reception of television signals on an RF band of 900 MHz by taking advantage of revised FCC regulations which have allocated the band of 902 MHz to 928 MHz for this application.
Moreover, the present invention seeks to provide for a flexible wireless transmission and reception of television signals in a manner which provides for the best possible television picture at the remote television set using the least costly combination of components.
Accordingly, it is an object of the present invention to provide a wireless audio and video signal transmitter and receiver system apparatus capable of accepting both a modulated audio/video signal and baseband audio and baseband video signals as inputs to a transmitter.
It is additionally an object of the present invention to provide for the user to select between the external modulated audio/video signal and external baseband audio/video signals as inputs to the transmitter.
It is yet a further object of the present invention to convert the external modulated audio/video signal input and the baseband audio and video signal inputs to common audio subcarrier and baseband video signals to permit the selection between said inputs to be performed with a mechanical switch in place of costly RF switching components.
It is still a further object of the present invention to provide a receiver which down converts a received RF signal to an IF frequency corresponding to a modulated audio/video signal in turn corresponding to a standard television channel frequency, so as to provide for the direct interface to a television set.
It is a further object of the present invention to provide for the user to select between two RF channels of 914 MHz and 919 MHz for transmission of an audio/video signal by providing for the user selectable AM modulation at IF frequencies of 245 MHz and 250 MHz.
It is an object of the present invention to provide for filtering of the received audio/video signal without the use of SAW filters.
These and other objects of the invention will become apparent in light of the present specification and drawings.